1. Swiss and C3H male mice developed papillomas of the forestomach after a single feeding of 9,10-dimethyl-1,2-benzanthracene, 20-methylcholanthrene, or 3,4-benzpyrene. After six or more feedings, many of the tumors were malignant. The earliest papilloma was observed after 4 weeks from the commencement of treatment and the earliest carcinoma after 12 weeks. The high tumor yield and short latent period are attributed mainly to the high concentrations of carcinogen used.

  2. When the carcinogen was administered on an empty stomach (following the substitution of milk for Purina for 3 days, followed by overnight starvation), the yields of tumors appeared higher than when given after only overnight starvation.

  3. Unlike the other carcinogens tested, a single dose of 1,2,5,6-dibenzanthracene did not produce tumors of the forestomach, under the conditions of the experiment.

  4. No tumors of the glandular mucosa of the stomach were obtained in any of the animals.

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This work was supported in part by grants from the Damon Runyon Fund (1951–53).

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©1955 American Association for Cancer Research.
1955
Cancer Research, Inc.